Fuse-isolator - actuator

Abstract

The invention provides an isolating fusible link, in series with a transformer primary circuit breaker device, for producing an isolating gap after an occurrence of a primary fault condition. More particularly, the invention provides an apparatus comprising a power transformer primary circuit breaker device adapted to be electrically connected in a circuit and including a first contact, and a second contact movable out of engagement with the first contact to open the circuit and movable into engagement with the first contact to close the circuit; and a fuse device including a fusible link connected in electrical series with the breaker device, and adapted to fuse upon an overcurrent condition in the circuit, and structure for moving and maintaining the second current out of engagement with the first contact in response to fusing of the fusible link.

I claim: 
     
       1. An apparatus comprising: a power transformer primary circuit breaker device adapted to be electrically connected in a circuit and including a first contact, a second contact movable out of engagement with said first contact to open the circuit and movable into engagement with said first contact to close the circuit, and temperature out of engagement with said first contact in response to a fault condition in the circuit; and   a fuse device including a fusible link connected in electrical series with the breaker device, and adapted to melt upon an overcurrent condition in the circuit, and means separate from said trip means and for moving said second contact out of engagement with said first contact in response to fusing out of said fusible link, wherein melting of said fusible link produces an arc, and wherein production of the arc causes said means separate from said trip means to move said second contact out of engagement with said first contact.   
     
     
       2. An apparatus in accordance with claim 1 wherein said fuse device further includes means for preventing movement of said second contact into engagement with said first contact after said moving means moves with second contact out of engagement with said first contact. 
     
     
       3. An apparatus in accordance with claim 1 wherein said fuse device also includes a cylinder defining a bore, and a piston dividing the bore into a first chamber and a second chamber, wherein said fusible link is located in said first chamber, and wherein said moving means further includes means for moving said piston in the direction increasing the volume of said first chamber in response to melting of said fusible link. 
     
     
       4. An apparatus in accordance with claim 3, wherein said moving means further includes a mechanical link communicating with said piston and said second contact such that said second contact is moved out of engagement with said first contact in response to movement of said piston in the direction increasing the volume of said first chamber. 
     
     
       5. An apparatus in accordance with claim 3 wherein said means for moving said piston comprises material located in said first chamber and adapted to expand in response to melting of said fusible link. 
     
     
       6. An apparatus in accordance with claim 5 wherein said fusible link produces an arc upon melting, and wherein said material vaporizes in response to heat produced by the arc. 
     
     
       7. An apparatus in accordance with claim 4 wherein said fuse device further includes means for preventing movement of said second contact into engagement with said first contact after said second contact moves out of engagement with said first contact, said means for preventing movement of said second contact into engagement with said first contact comprising means for preventing movement of said piston in the direction decreasing the volume of said first chamber. 
     
     
       8. An apparatus in accordance with claim 7 wherein said piston has therein a recess, and wherein said means for preventing movement of said piston comprises said recess, and a projection which is fixed in position with respect to said cylinder and which extends into said recess in response to movement of said piston in the direction increasing the volume of said first chamber, thereby preventing movement of said piston in the direction decreasing the volume of said first chamber. 
     
     
       9. An apparatus in accordance with claim 7 wherein said bore further includes a first section having a first inner diameter, and a second section having a second inner diameter greater than said first inner diameter, wherein said piston is located at least partially in said first section when said second contact is in engagement with said first contact, wherein said second contact is moved out of engagement with said first contact in response to movement of said piston completely into said second section, and wherein said piston expands radially outwardly upon complete movement thereof into said second section, thereby preventing movement of said piston in the direction decreasing the volume of said first chamber. 
     
     
       10. A fuse device for use with a power transformer breaker device adapted to be electrically connected in a circuit and including a first contact, and a second contact movable into and out of engagement with the first contact for respectively closing and opening the circuit; said fuse device comprising a cylinder defining a bore, a piston, dividing the bore into a first chamber, and a second chamber, a fusible link in said first chamber, adapted to be connected in electrical series with the power transformer breaker device and adapted to fuse upon an overcurrent condition in the circuit, and means for moving the second contact out of engagement with the first contact in response to fusing of said fusible link and including means for moving said piston in the direction increasing the volume of said first chamber. 
     
     
       11. An apparatus in accordance with claim 10 in electrical series connection with a transformer primary. 
     
     
       12. An apparatus for use with a power transformer having a primary side, said apparatus comprising: a power transformer breaker device adapted to be electrically connected in series with the primary side to define a portion of a circuit including the power transformer primary side, when said apparatus is in use, said breaker device further including a contact assembly and a conductive rod defining the portion of the circuit, said conductive rod being movable out of engagement with said contact assembly to open the circuit and moveable into engagement with said contact assembly to close the circuit; and   a fuse device including a cylinder defining a bore, a piston dividing the bore into a first chamber and a second chamber, a mechanical link between said piston and said conductive rod and adapted to move said conductive rod out of engagement with said contact assembly in response to movement of said piston in the direction increasing the volume of said first chamber, a fusible link in said first chamber and in electrical series connection with the portion of the circuit, and adapted to fuse upon an overcurrent condition in the circuit, and material located in said first chamber and adapted to expand in response to fusing of said fusible link, thereby moving said piston in the direction increasing the volume of said first chamber.   
     
     
       13. An apparatus comprising: a power transformer primary circuit breaker device adapted to be electrically connected in a circuit and including a first contact, and a second contact movable out of engagement with said first contact to open the circuit and movable into engagement with said first contact to close the circuit; and   a fuse device including a cylinder defining a bore, a piston dividing the bore into a first chamber and a second chamber, a fusible link in said first chamber, connected in electrical series with the breaker device, and adapted to fuse upon an overcurrent condition in the circuit, and means for moving said second contact out of engagement with said first contact in response to fusing of said fusible link and including means for moving said piston in the direction increasing the volume of said first chamber.   
     
     
       14. An apparatus in accordance with claim 13 wherein fusing of said fusible link produces an arc, and wherein said moving means moves said second contact in response to production of the arc. 
     
     
       15. An apparatus in accordance with claim 13 wherein said fuse device further includes means for preventing movement of said second contact into engagement with said first contact after said moving means moves said second contact out of engagement with said first contact. 
     
     
       16. An apparatus in accordance with claim 13 wherein said moving means further includes a mechanical link communicating with said piston and said second contact such that said second contact is moved out of engagement with said first contact in response to movement of said piston in the direction increasing the volume of said first chamber. 
     
     
       17. An apparatus in accordance with claim 13 wherein said means for moving said piston comprises material located in said first chamber and adapted to expand in response to fusing of said fusible link. 
     
     
       18. An apparatus in accordance with claim 17 wherein said fusible link produces an arc upon fusing, and wherein said material vaporizes in response to heat produced by the arc. 
     
     
       19. An apparatus in accordance with claim 16 wherein said fuse device further includes means for preventing movement of said second contact into engagement with said first contact after said second contact moves out of engagement with said first contact, said means for preventing movement of said second contact into engagement with said first contact comprising means for preventing movement of said piston in the direction decreasing the volume of said first chamber. 
     
     
       20. An apparatus in accordance with claim 19 wherein said piston has therein a recess, and wherein said means for preventing movement of said piston comprises said recess, and a projection which is fixed in position with respect to said cylinder and which extends into said recess in response to movement of said piston in the direction increasing the volume of said first chamber, thereby preventing movement of said piston in the direction decreasing the volume of said first chamber. 
     
     
       21. An apparatus in accordance with claim 19 wherein said bore further includes a first section having a first inner diameter, and a second section having a second inner diameter greater that said first inner diameter, wherein said piston is located at least partially in said first section when said second contact is in engagement with said first contact, wherein said second contact is moved out of engagement with said first contact in response to movement of said piston completely into said second section, and wherein said piston expands radially outwardly upon complete movement thereof into said second section, thereby preventing movement of said piston in the direction decreasing the volume of said first chamber. 
     
     
       22. An apparatus for use with a power transformer having a primary side, said apparatus comprising: a power transformer breaker device adapted to be electrically connected in series with the primary side to provide a current path in electrical series with the power transformer primary side, when said apparatus is in use, said breaker device further including mechanical means for selectively serving the current path, said means for selectively serving the current path including a contact assembly and a conductive rod movable out of engagement with said first contact to severe the current path; and   a fuse device including a fusible link in electrical series with said power transformer breaker device, said fusible link being adapted to fuse when current flow through the current path exceeds a predetermined amount, said fuse device further including means operable on said mechanical means for severing the current path in response to fusing of said fusible link, said means in said fuse device for mechanically severing said current path including a cylinder, a piston slidably housed in said cylinder and defining a first chamber and a second chamber in said cylinder, said first chamber housing said fusible link, and an insulating rod which is movable with said piston and which is attached to said conductive rod so as to separate said conductive rod from said contact assembly in response to movement of said piston consequent to fusing of said fusible link.   
     
     
       23. An apparatus in accordance with claim 22 wherein said first chamber houses material adapted to expand in response to fusing of said fusible link, wherein fusing of said fusible link produces an arc, and wherein said material expands in response to heat produced by the arc. 
     
     
       24. An apparatus in accordance with claim 22 in electrical series connection with a transformer primary. 
     
     
       25. An apparatus comprising: a power transformer having a primary side;   a power transformer breaker device electrically connected in series with said primary side to define a portion of a circuit including said power transformer primary side, when said apparatus is in use, said breaker device further including a contact assembly and a conductive rod defining the portion of the circuit, said conductive rod being movable out of engagement with said contact assembly to open the circuit and movable into engagement with said contact assembly to close the circuit; and   a fuse device including a cylinder defining a bore, a piston dividing the bore into a first chamber and a second chamber, a mechanical link between said piston and said conductive rod and adapted to move said conductive rod out of engagement with said contact assembly in response to movement of said piston in the direction increasing the volume of said first chamber, a fusible link in said first chamber and in electrical series connection with the portion of the circuit, and adapted to fuse upon and overcurrent condition in the circuit, and material located in said first chamber and adapted to expand in response to fusing of said fusible link, thereby moving said piston in the direction increasing the volume of said first chamber.